In Vitro Conversion of ß-Carotene to Retinal in Bovine Rumen Fluid by a Recombinant ß-Carotene- 15, 15’-Monooxygenase

Abstract

Pasture-fed cattle yield carcasses with yellow fat; consumers often reject the resulting meat products because they assume they come from old and/or culled animals. Recombinant bacteria expressing beta-carotene 15, 15'-monooxygenase, introduced into the rumen of the animal, might help to reduce the coloration since this enzyme converts carotene to retinal, thereby eliminating the source of yellowness. The goal of this work was to evaluate the effect of a recombinant beta-carotene 15, 15'-monooxygenase (BCMO1) from Gallus gallus, expressed in Escherichia coli. The genetically modified microbe was introduced into ruminal fluid, and carotene conversion to retinal was measured. Under optimum conditions the enzyme produced 6.8 nmol of retinal per 1 mg of protein in 1 hour at 37 °C. The data on in vitro digestibility in ruminal fluid showed no differences in beta-carotene breakdown or in retinal production (p > 0.1) between E. coli with pBAD vector alone and E. coli with pBAD/BCMO1. The pBAD/BCMO1 plasmid was stable in E. coli for 750 generations. These results indicate that the protein did not break beta-carotene into retinal in ruminal fluid, perhaps due to its location in the periplasmic space in E. coli. Future research must consider strategies to release the enzyme into the rumen environment.

Antitumor Effects of Saffron-Derived Carotenoids in Prostate Cancer Cell Models

“…Studies in animal models and with cultured human malignant cell lines have demonstrated antitumor and anticancer activities of SE [11, 14–19]. The mechanisms underlying cancer chemopreventive activities of SE include (i) inhibition of synthesis of DNA and RNA, but not protein [16]; (ii) ability to scavenge free radicals [20, 21]; (iii) involvement in the metabolic conversion of carotenoids to retinoids [22]; (iv) direct or indirect interactions with topoisomerase II [16]; (v) promotion of interactions mediated via lectins [23]; and (vi) downregulation of the expression of the catalytic subunit of the human telomerase, hTERT [24]. …”

Molecular Properties of β-Carotene Oxygenases and Their Potential in Industrial Production of Vitamin A and Its Derivatives

“…The characteristics of BCO1 and BCO2 from various organisms are summarized in Table 1. BCO1 derived from different sources (hereafter, BCO1s) are mainly found in animals, such as mammals [8,20,[26][27][28][29][30][33][34][35], chicken [22][23][24][25], Caenorhabditis elegans [21,44], and uncultured marine bacterium [32]. BCO2 derived from different sources (hereafter, BCO2s) have been reported in a wide range of organisms, including animals [11,15,[38][39][40], Saccharomyces cerevisiae [42], and plants such as apple [36], Arabidopsis thaliana [37], chrysanthemum [36], osmanthus [36], potato [41], rose [36], and saffron [43].…”

“…BCO1 derived from chicken, and expressed in E. coli, showed a higher specific activity than that expressed in BHK cells, indicating that activity of BCO seems to be affected by enzyme expression conditions such as the expression vector and host cells. For example, under the pBAD system, BCO activity was approximately 20 times higher than under the pET system [24,25]. On the other hand, purified human-derived BCO1, expressed in SF9 cells showed a higher specific activity and catalytic efficiency than that expressed in E. coli cells [8,29].…”

Digestive recovery of sulfur‐methyl‐l‐methionine and its bioaccessibility in Kimchi cabbages using a simulated in vitro digestion model system

“…13,14 Good correlations in bioaccessibility have been found between in vitro studies and humans. 15 -17 Studies on bioaccessibility of SMM in human from food sources are not up to date. It could be very valuable to examine how SMM could be modulated under the human gastrointestinal (GI) tract.…”

“…In vitro digestion systems, which simulate the human gastrointestinal tract, have been used for predicting digestive stability and bioaccessibility of a variety of micronutrients from fruits and vegetables . Good correlations in bioaccessibility have been found between in vitro studies and humans . Studies on bioaccessibility of SMM in human from food sources are not up to date.…”